上海市中心城区某幼儿园一例肺结核患者密切接触者筛查情况分析

目的 分析上海市中心城区某幼儿园1例肺结核患者密切接触者筛查情况,为完善托幼机构结核病防控提供依据。方法 分别于2019年2月15日和2019年3月14日对2019年1月14日确诊的上海市中心城区某幼儿园1例肺结核教职工的128名密切接触者进行流行病学筛查,包括肺结核疑似症状筛查、结核分枝杆菌潜伏感染检测[γ干扰素释放试验(interferon-γ releaseassays,IGRA)]、胸部X线摄片或CT检查,以及痰涂片和痰培养;并对不同特征密切接触者(性别、卡介苗接种情况、有无疑似肺结核症状、近期呼吸系统疾病就诊史、暴露等级)的潜伏感染情况进行分析。结果 128名密切接触者中,幼儿107名(83.59%),教职工21名(16.41%)。疑似肺结核症状阳性率为5.47%(7/128),其中幼儿为5.61%(6/107),教职工为4.76%(1/21)。两次筛查中,共125名密接者(3名幼儿拒绝检测)进行了IGRA检测,阳性者11例(8.80%),包括幼儿4例(3.20%),教职工7例(5.60%)。肺结核的检出率为0.78%(1/128),总潜伏感染率为8.06%(10/124;排除1例确诊和3名未进行IGRA检测的幼儿),其中幼儿的潜伏感染率[2.91%(3/103)]明显低于教职工[33.33%(7/21)],差异有统计学意义(χ²=21.773,P=0.000)。7例潜伏感染教职工进行了3、6、12个月末的胸片随访,3例潜伏感染幼儿进行了3个月的预防性抗结核药品干预治疗;经1年随访观察均无续发结核病患者。单因素分析显示,接种卡介苗者的潜伏感染率[5.13%(6/117)]与未接种者(4/7)比较,差异有统计学意义(Fisher精确概率法,P=0.001);高暴露等级者的潜伏感染率[17.07%(7/41)]明显高于中暴露等级者 [3.61%(3/83)],差异有统计学意义(χ²=5.012,P=0.025)。结论 应加强托幼机构教职员工健康体检,积极行IGRA检测筛查结核病患者密切接触者,尤其是无卡介苗接种史和高暴露者。对结核分枝杆菌潜伏感染者行预防性服药或胸片随访对防止续发肺结核有重要意义。

Analysis of screening of close contacts of a tuberculosis patient in a kindergarten in downtown Shanghai

Objective To analyze the screening close contacts of a tuberculosis patient in a kindergarten in the downtown area of Shanghai, and to provide references for improving the prevention and control of tuberculosis in nurseries and kindergartens. Methods Epidemiological screening, including suspected symptoms screening, latent Mycobacterium tuberculosis infection (IGRA), chest X-rays or CT scans, and sputum smears and cultures were conducted on February 15, 2019 and March 14, 2019 among 128 close contacts of a staff member who was diagnosed as tuberculosis on January 14, 2019 in a kindergarten in downtown Shanghai. The latent infection status of close contacts with different characteristics (gender, BCG vaccination status, suspected pulmonary tuberculosis symptoms, recent medical history of respiratory disease, and exposure level) was analyzed. Results Among the 128 close contacts, 107 (83.59%) were children and 21 (16.41%) were faculty. The positive rate of suspected tuberculosis symptoms was 5.47% (7/128), which were 5.61% (6/107) in children and 4.76% (1/21) in faculty. In the two screening tests, 125 close contacts (3 children refused to be tested) were tested for IGRA, and 11 cases (8.80%) were positive, including 4 children (3.20%) and 7 teaching staff (5.60%). The detection rate of tuberculosis was 0.78% (1/128), and the total latent infection rate was 8.06% (10/124, excluding 1 case confirmed and 3 children without IGRA test). The latent infection rate of children (2.91%, 3/103) was significantly lower than that of teaching staff (33.33%, 7/21), and the difference was statistically significant (χ²=21.773, P=0.000). Seven teaching staffs of latent infection were followed up by chest film at the end of 3, 6 and 12 months, and 3 children of latent infection were treated with prophylactic anti-tuberculosis drug intervention for 3 months. After one year follow-up observation, there was no patient with secondary tuberculosis. Univariate analysis showed that the latent infection rate of BCG vaccinated patients (5.13%, 6/117) was statistically significant compared with that of non-vaccinated patients (4/7) (Fisher’s exact probability method, P=0.001). The latent infection rate of high exposure level persons (17.07%, 7/41) was significantly higher than that of medium exposure level persons (3.61%, 3/83), and the difference was statistically significant (χ²=5.012, P=0.025). Conclusion Health examination of staff in nurseries and nursery institutions should be strengthened, and IGRA testing should be actively carried out to screen close contacts of tuberculosis patients, especially those without BCG vaccination history and high exposure. It is of great significance to take preventive therapy or follow up with radiography in the patients with latent Mycobacterium tuberculosis infection for the prevention of secondary tuberculosis.